**Core Concept**
Digoxin toxicity is a significant concern in patients treated with this cardiac glycoside. It arises due to the accumulation of digoxin in the body, disrupting normal cardiac function and electrolyte balance. The risk factors for digoxin toxicity include hypokalemia, hypomagnesemia, hypercalcemia, and impaired renal function.

**Why the Correct Answer is Right**
Digoxin works by inhibiting the Na+/K+-ATPase pump, leading to an increase in intracellular sodium and a subsequent increase in intracellular calcium. This enhances cardiac contractility but also increases the risk of arrhythmias. Hypokalemia and hypomagnesemia exacerbate digoxin toxicity by increasing the sensitivity of the Na+/K+-ATPase pump to digoxin, leading to further cardiac depression and arrhythmias. Hypercalcemia also increases the risk of digoxin toxicity by increasing the amount of calcium available to bind to the cardiac myocyte, leading to an increase in intracellular calcium and cardiac contractility.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it is a known precipitant of digoxin toxicity. Hypokalemia and hypomagnesemia are common in patients taking diuretics, which increases the risk of digoxin toxicity.
**Option B:** This option is incorrect as hypercalcemia is a known risk factor for digoxin toxicity. It increases the amount of calcium available to bind to the cardiac myocyte, leading to an increase in intracellular calcium and cardiac contractility.
**Option C:** This option is incorrect as impaired renal function is a known risk factor for digoxin toxicity. Digoxin is excreted by the kidneys, and impaired renal function leads to the accumulation of digoxin in the body, increasing the risk of toxicity.

**Clinical Pearl / High-Yield Fact**
Patients taking digoxin should be monitored for signs of toxicity, including bradycardia, arrhythmias, and nausea. Additionally, they should be advised to avoid diuretics and potassium-wasting medications, which can increase the risk of hypokalemia and hypomagnesemia.

**Correct Answer: A, B, C**